Silva, Felipe EnnesPacca, Luciana GosiLemos, Lisley PereiraGusmao, Almerio Camarada Silva, Odair DiogoDalponte, Julio CesarFranco, Caetano L. B.Santana, Marcelo IsmarBuss, GersonEl Bizri, Hani R.2023-05-082023-05-082022-11PII S0030605322000655http://hdl.handle.net/10919/114971Assessing the conservation status of species is essential for implementing appropriate conservation measures. A lack of evidence of threats, rather than showing an absence of impacts, could reflect a lack of studies on how human activities could result in species population declines. The range of Prince Bernhard's titi monkey Plecturocebus bernhardi is restricted to the Arc of Deforestation, a deforestation hotspot in south-eastern Amazonia. Despite this, it is categorized as Least Concern on the IUCN Red List. To reassess the conservation status of P. bernhardi, we carried out surveys during 2015-2017 to delimit the geographical distribution of the species and estimate its population density and abundance. We then used spatial predictive modelling to examine future habitat and population loss within its range. Plecturocebus bernhardi occurs over an area of 131,295 km(2). Its mean group size was 2.8 individuals/group and its density 10.8 individuals/km(2) and 3.8 groups/km(2). Habitat loss was estimated to be 58,365 km(2) (32.3% of its current range) over the next 24 years (three P. bernhardi generations) under a conservative governance model of deforestation and 105,289 km(2) (58.3%) under a business-as-usual model. These numbers indicate that P. bernhardi is threatened and should be categorized as Vulnerable, at least, using the IUCN Red List criteria. We recommend the reassessment of other Least Concern primate species from the Arc of Deforestation using a similar approach.application/pdfenCreative Commons Attribution 4.0 InternationalAmazon rainforestArc of Deforestationconservation statushabitat lossIUCN Red ListLeast ConcernPlecturocebus bernhardiprimate conservationArticle - Refereedhttps://doi.org/10.1017/S00306053220006555661365-3008